STAF: Database of Time-Varying Surface Appearance

About the Database

Traditional computer graphics rendering generally assumes that the appearance of surfaces remains static over time. Yet, there are a number of natural processes that cause surface appearance to vary dramatically, such as burning of wood, wetting and drying of rock and fabric, decay of fruit skins, or corrosion and rusting of steel and copper. To investigate time-varying surface appearance, we formulate this problem as TSV-BRDF (Time-and-Space-Varying BRDF),




and used a dome to acquire a database of 26 examples covering a range of phenomena, including burning, corrosion, drying on smooth and rough surfaces, and decay. The following image is a brief overview:



Basically, there are 3 steps to acquire and process each example:

  • First, at each time step, we have acquired images from 16 views and 80 lighting directions from the dome (thus 1,280 measurement in total). All of the acquired images are high dynamic range by taking two images under different exposures. For each example, we usually captured 30 time steps. Then we performed both geometrical and radiometrical normalization so that the acquired images are normalized to  400*400 pixels (other resolution as well) for each lighting and view direction with perfect uniform white lighting.

  • Second,  we fitted a simple BRDF model for each pixel at each time step. The BRDF model we used are Lambertian + a simplfied Torrance-Sparrow model. With this fitting, the reflectance of each sample at each time step will be represented by a set of BRDF parameters.

  • Finally, we proposed a novel nonlinear STAF  (Space-Time Appeareance Factorization) model to represent the TSV-BRDF, which not only can accurately reconstruct the original data but also gives us much more controllability for novel rendering applications.

The release of this database thus includes the above 3 parts for each example: the raw measurement, the fitted BRDF parameters, and the STAF factorization results. Due to the space limitation, we can not release all the 1,280 raw measurements. Instead, we selected 1 view and 6 lighting directions (thus 6 measurement in total) for each example at each time step. More detailed information about the database can be found here.

The acquisition and the modeling details of our work can be referred to the following paper:

"Time-varying Surface Appearance: Acquisition, Modeling, and Rendering,"
J. Gu, C. Tu, R. Ramamoorthi, P. Belhumeur, W. Matusik and S. K. Nayar,
ACM Trans. on Graphics (also Proc. of ACM SIGGRAPH),
Jul, 2006.
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STAF Database Home
Contact: staf@lists.cs.columbia.edu
Last modified: 08/28/2006